EP 0848504 A2 19980617 - Quadrature phase shift keying spread spectrum communication system
Title (en)
Quadrature phase shift keying spread spectrum communication system
Title (de)
Spreizspektrumübertragungssystem mit quaternärer Phasenumtastung
Title (fr)
Système de communication à spectre étalé à modulation de phase à quatre états
Publication
Application
Priority
- JP 33384296 A 19961213
- JP 25077197 A 19970916
Abstract (en)
A spread spectrum transmitter and receiver are provided wherein data can be accurately decoded by removing the effect of mutual interference of the quadrature component and in-phase component even when there is carrier frequency error. In a method of spread spectrum communication using a QPSK modulation system, there are provided: a demodulating circuit that receives and demodulates a signal transmitted with a prescribed time difference Td applied between the IQ components; correlators that find the mutual correlation of the IQ components and spreading code; a sampling circuit that samples their output signals; a phase calculator that calculates the phase from the ratio of the IQ components of these output signals; a differential decoding circuit that performs differential decoding on this output signal; an automatic frequency control circuit that corrects the frequency error of this output signal; a decoding circuit that decodes the data of these output signals; and a clock recovery circuit that recovers a clock. Data is decoded by performing clock recovery and correction of the carrier frequency error using the vector of the received signal at time point t and the vector of the received signal at time point (t + Td) at the receiver. <IMAGE>
IPC 1-7
IPC 8 full level
H04B 1/707 (2011.01)
CPC (source: EP US)
H04B 1/707 (2013.01 - EP US); H04B 1/709 (2013.01 - EP US)
Designated contracting state (EPC)
AT BE CH DE DK ES FI FR GB GR IE IT LI LU MC NL PT SE
DOCDB simple family (publication)
DOCDB simple family (application)
EP 97310052 A 19971212; US 98702497 A 19971209